Means for maintaining constant the voltage of an electric circuit.



PATENTE D MAR. 5, 1907. T. MARSHALL.

CIRCUIT.

LIYPLIOATIOH FILED JAN. 10. 1907.

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MEANS FOR MAINTAINING CONSTANT THE VGLTAGE OF AN ELECTRIC WWJa UNITED STAT FATE.

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THOMAS MARSHALL, OF ()i'lK AGQ iLLl NOE.

MEANS FOR MAlNTAlNlNG CONSTANT THE VOLTAGE OF AN ELECTRKI ClRCUlT,"

Patented March 5, 1907.

Application filed January 3,0. 1907 Serial No. 351,683.

.To all whom it may concern:

Be it known that I, THOMAS MARsuALL, a

cage, in the county of Cook and State of llli nois, have invented certain new and useful Improvements in Means for Maintaining Constant the Voltage of an Electric Circuit, of which the following is a full, clear, and exact specification.

This invention relates to a system of circuits and devices for maintaining constant the voltage of an electric circuit; and it has for its primary object to provide improvements whereby as the voltage of such circuit falls below a certain value the deficiency will be automatically supplied,

- Another object oi the invention. is to util ize the current of a variablevoltage circuit for neutralizing or opposing the field oi an electric generator and to add to the circuit in which a constant voltage is to be 1naintained the voltage which results in the genes ator from a variation in the strength of such field.

With the view to the attainment of ends and the accomplishment of certain other objects, which will hereinafter appear, theinvention consists in the features of novelty which will now be described with reference to the accompanying drawing and more particularly pointed out in the claims.

The said drawing is a diagrammatic illustration of the circuits and devices co'nstituting an embodiment of this invention.

-A is a circuit of variable voltage, and B a circuit of constant voltage.

C is a generator which is connected with these two circuits and which is provided with two fields D E, which are so wound as to oppose each other, The field D is connected across the circuit A. by conductor 11, while the field E is connected across some suitable source of constant potential G, the strength of field E being equal to that ol field D when the voltage of the variable-voltage circuit A is equal to that to be maintained across the constant voltage circuit B.

The generator C is connected to a motor H, which in th1s cxemphiication of the inventlon 1s represented as an electric motor con nected across the eonstant-voltage circuit B l by conductor i and being directly connected with the generator (I in any suitable way, so

as to drive the latter.

With this arrangement of devices and circuits it will be seen that the field E, being constant, and the field l), varying with every variation in the variable-voltage circuit A, the voltage generated by the generator 0 will be directly proportional to the dii'l'crence in voltage between the two circuits A is, and as a consequence the deficiency resulting in a decrease of voltage in A will be automatically supplied to B, and the voltagcin A again rises to normal the value of field D will be proportionately increased until eventually completely countor-balancing the iield iii, and when the neutralization of the two fields is complete this compensating supply of current ii'Oll'l the generator U will cease. in order to perfectly accomplish this result, it is oi course quite essential that the speed of the generator i) remain approximately constant, and for that reason it is desirable that it be driven by an electric motor, such as H, and that this motor be supplied with current from the constant-voltage circuit, as shown.

In order that the invention might be fully understood by those skilled in the art, the details of the foregoing embodiments thereof have been thus specifically described; but

ivhat 1 claim as new therein, and desire to secure by Letters Patent, is-

l. in a system for maintaining a constant voltage inan electric circuit, the combination 01' a variable-voltage circuit, a generator having a field connected across the variable voltage circuit, a constant-voltage circuit connected with the generator and the varitilde-voltage circuit, and an unvarying field opposing or neutralizing the first said field.

2. in a system for maintaining a constant voltage in an electric circuit, the combination oi a variable-voltage circuit, a generator having a field connected across the variablevoltage circuit, a c mstant-voltage circuit connected with the generator and the variable-voltage circuit, a second field ar ranged to oppose the first said field, and a ond said field.

oonstan t-potcr tial circuit supplying the sec- 3. In a system of rneinteining a cons-tent In testimony whereof I have signed my IO voltage in an electric circuit, a generator havname to this specification, in the presence 01 ing a field connected across the ,vnriabletWo subscribing Witnesses, on this 4th day of voltage circuit, a constnnhvoltage circuit January, A. D. 1907. connected with the generztt'er and the va- 4 A i rieble-voltege circuit,-an unvarying field op rHIOMAS MARSHALL posing or neutralizing the first seid field, and Witnesses:

a motor for driving the generator connected H. Jocnnm, J12, with the c0nste-nt-v0ltage circuit. FRANCIS M. Lowns. 

